This laboratory is interested in all aspects of bionomics, physiology and vectorial capacity in Aedes mosquitoes, with emphasis on species of Stegomyia and Finlaya. It serves as the W.H.O. Collaborating Centre for Maintenance of Strains of Aedes: over 35 species are maintained, the world's best "mosquito zoo." Over 200 strains of A. aegypti are kept, including geographic strains, highly inbred lines and strains with multiple genetic markers. Linkage maps have been constructed (n equals 3) and nearly 100 genes have been mapped. Special interest is in single genes conferring resistance to vertebrate pathogens. Monofactorial control has been demonstrated for genes controlling bird malaria, filariasis (Brugia, Dirofilaria and Foleyella) and LaCrosse Encephalitis Virus. Current emphasis is on Aedes triseriatus, the treehole mosquito, primary midwestern vector of LaCrosse Encephalitis. Census work on an isolated 15 acre tract of woods with 120 treeholes has shown an adult population of about 1000 females during July-September. Longevity is much greater than for other mosquitoes. A survey of 40 geographic strains of A. triseriatus has shown marked variation in susceptibility and transmission of LAC, ranging from 10 to 95% transmission. Toxorhynchites brevipalpis for control of treehole mosquitoes is being developed. Studies on photoperiod-induced diapause of A. atropalpus have shown that control can be achieved by light pulsing in the evening during August-September; this treatment prevents production of diapausing, cold-hardy eggs. BIBLIOGRAPHIC REFERENCES: Petersen, J.L., J.R. Larsen & G.B. Craig, Jr. 1976. Palp-antenna, a homeotic mutant in Aedes aegypti. Jour. Heredity 67:71-78. Saul, S., P. Guptavanij and G.B. Craig, Jr. 1976. Genetic variability at an esterase locus in Aedes aegypti. Ann. Entomol. Soc. Amer. 69(1): 73-79.